Glossary

Flag semaphore indicating the Number 0. This shape represents both the Number 0 (Flag Semaphore) and the Letter K (Flag Semaphore).

Before...

International Morse Code sequence representing the number 0.

The flag represents the numerical value of zero.

Flag semaphore indicating the number 1. This shape is the Number 1 (Flag Semaphore) and the Letter A (Flag Semaphore).

Before delivering...

International Morse Code sequence representing the number 1.

The flag represents the numerical value of one.

Flag semaphore indicating the number 2. This shape is the Number 2 (Flag Semaphore) and the Letter B (Flag Semaphore).

Before delivering...

International Morse Code sequence representing the number 2.

The flag represents the numerical value of two.

Flag semaphore indicating the Number 3. This shape represents both the Number 3 (Flag Semaphore) and the Letter C (Flag Semaphore).

Before...

International Morse Code sequence representing the number 3.

The flag represents the numerical value of three.

Flag semaphore indicating the Number 4. This shape represents both the Number 4 (Flag Semaphore) and the Letter D (Flag Semaphore).

Before...

International Morse Code sequence representing the number 4.

Flag semaphore indicating the Number 5. This shape represents both the Number 5 (Flag Semaphore) and the Letter E (Flag Semaphore).

Before...

International Morse Code sequence representing the number 5.

Flag semaphore indicating the Number 6. This shape represents both the Number 6 (Flag Semaphore) and the Letter F (Flag Semaphore).

Before...

International Morse Code sequence representing the number 6

Flag semaphore indicating the Number 7. This shape represents both the Number 7 (Flag Semaphore) and the Letter G (Flag Semaphore).

Before...

International Morse Code sequence representing the number 7.

Flag semaphore indicating the Number 8. This shape represents both the Number 8 (Flag Semaphore) and the Letter H (Flag Semaphore).

Before...

International Morse Code sequence representing the number 8.

Flag semaphore indicating the Number 9. This shape represents both the Number 9 (Flag Semaphore) and the Letter I (Flag Semaphore).

Before...

International Morse Code sequence representing the number 9.

A position or direction towards the rear (stern) of a vessel relative to a specific point of reference on the boat.

In maritime terminology,...

To reduce in intensity, force, or degree, especially in relation to wind, waves, or other marine conditions.

Abate refers to the lessening or...

The position or direction at right angles to the centreline or keel of a vessel, typically on either side of the boat.

Abeam describes...

Something done openly, honestly, and straightforwardly without deceit or dishonesty. It originates from pirates hiding crew members below deck...

The area of a boat or ship located on the main deck or any higher deck levels. This area is typically exposed to the elements and is where...

An unintentional and often abrupt change in a sailing vessel's course that causes the boom to swing violently across the boat, typically due to a...

The International Maritime Signal Flag Alpha.

Meaning

I have a diver down; keep well clear at slow speed.
If appended with a Numeral...

A vessel that is floating without being anchored, moored, or under control, often at the mercy of wind and currents. 

Adrift describes a...

The RYA Advanced Pilotage course focuses on navigating in challenging conditions, such as night cruising or confined waterways. Participants...

The state of being buoyant and on the water's surface, not submerged or sinking. 

Afloat is a term commonly used in the maritime world to...

The rear or stern section of a vessel, towards the back of the boat or ship.

Aft is a directional term used to describe the position or...

The portion of a vessel's deck located towards the stern, or rear, of the ship.

The after deck, sometimes referred to as the aft deck, is a...

The situation when a vessel is stuck on the seabed or shore, unable to move freely in the water.

When a vessel is aground, the hull has come...

The direction in front of a vessel, typically along its forward course or heading.

In maritime terminology, ahead is commonly used to describe...

A nautical greeting or hail used to attract attention, signal presence, or establish communication between vessels or individuals at...

A type of watercraft that uses a cushion of pressurised air beneath its hull to reduce friction and enable movement over water, land, or other...

A maritime communication system that automatically transmits and receives vessel information such as position, speed, and course to enhance...

The side of a vessel that is sheltered from the wind, also known as the leeward side.

Alee is a nautical term used to describe the side of a...

This shape represents the Letter A (Flag Semaphore) and the Number 1 (Flag Semaphore).

The presumed signals are letters. The signaller...

International Morse Code sequence representing the letter A.

All at sea is a nautical term for a situation where a ship or boat is adrift or lost at sea without any clear direction or sense of location.

A position above the deck, typically in the rigging or on the masts of a ship.

Aloft is used to describe any position above a vessel's deck,...

The position or location next to a vessel, dock, or quay where a ship can be moored or secured. 

The term alongside is a fundamental concept...

Aloof originally had a different meaning than its modern-day use to describe someone emotionally distant. In maritime language, Aloof comes from...

Pronounced: AL-far

Letter "A" in the phonetic alphabet system.

Pronounced: AL-far

Letter "A" in the phonetic alphabet system.

A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent.

Amplitude...

A US-based organisation that provides sailing education, certification, and accreditation for sailing schools and instructors. 

The American...

The central part of a vessel, both longitudinally and laterally, located between the bow and stern.

Amidships is a crucial term in nautical...

A method of transmitting information by varying the strength (amplitude) of a carrier wave in proportion to the signal being sent.

Amplitude...

A heavy object, typically made of metal, designed to grip the seabed and hold a vessel in position.

An anchor is a crucial piece of equipment...

A designated area where a vessel can be securely anchored, typically marked on nautical charts and chosen for its safe holding ground and...

The moment when an anchor has been lifted off the seabed and is no longer holding the vessel in place.

The term "anchor aweigh" is a...

A black spherical day shape hoisted on a vessel to signal that it is anchored during daylight hours.

An anchor ball is a crucial piece of...

A small floating marker attached to an anchor to indicate its location on the seabed.

An anchor buoy is a vital piece of equipment used in...

A heavy-duty rope, chain, or wire used to secure a vessel to its anchor, ensuring it remains stationary in the water.

An anchor cable is a...

A white light displayed by a vessel at anchor to indicate its position to other vessels during the night or in poor visibility conditions.

An...

A dedicated storage compartment, typically located in the bow of a vessel, used to store the anchor and its associated gear, such as the rode and...

A fitting mounted on a boat's bow designed to guide, support, and secure the anchor and its rode during deployment and retrieval.

An anchor...

The maximum angle of heel at which a vessel can recover to an upright position without capsizing.

The Angle of Vanishing Stability (AVS) is a...

A US-based organisation that provides sailing education, certification, and accreditation for sailing schools and instructors. 

The American...

The area or direction behind a vessel, towards the stern.

Astern is a nautical term used to describe both a direction and a movement in...

A large, lightweight sail with an off-centre shape, designed for sailing off the wind, typically used to improve downwind performance.

An...

At loggerheads is a nautical term referring to two ships positioned with their respective loggers (wooden blocks used for securing the ship's...

This shape is used to gain the receiver's attention and is used at the beginning of a transmission. The message recipient responds with the...

A maritime communication system that automatically transmits and receives vessel information such as position, speed, and course to enhance...

An Autonomous Underwater Vehicle (AUV) is a self-propelled, unmanned underwater vehicle capable of operating independently without direct human...

An Autonomous Underwater Vehicle (AUV) is a self-propelled, unmanned underwater vehicle capable of operating independently without direct human...

The maximum angle of heel at which a vessel can recover to an upright position without capsizing.

The Angle of Vanishing Stability (AVS) is a...

Back (backing) describes the wind’s change in direction when it shifts counterclockwise (anti-clockwise). For example, if the wind shifts from...

To back a sail means to adjust it so that the wind blows on the opposite side from normal, causing the sail to push the boat in the opposite...

Sea area of the Met Office Shipping Forecast. Lies off northern Scotland near Bill Bailey’s Bank and the Orkney Islands.

Named for Bill Bailey’s...

A spherical shape or object used as a day signal to indicate a vessel's status or condition, such as being anchored or aground.

In maritime...